Rotatable disk



R. BLODGET ROTATABLE DISK PERPETUAL CALENDAR WITH Feb. 22, 1949.

INTERLACED SPIRAL FORMATIONS `2 sheets-sheet 1 Filed` Feb. 15, 1945l Feb. 22, 1949. R. BLODGET ROTATABLE DISK PERPETUAL'CALENDAR WITH INTERLACED SPIRAL FORMATIONS 2 Sheets-Sheet 2 Filed Feb. 15, 1945 Patented Feb. 22, 1949 UNITED STATES PATENT -OFFICE ROTATABLE DISK, PERPETUAL CALENDAR WITH INTERLACED SPIRAL FORMATIONS My invention relates to certain new and useful improvements, and developments in the calendar art having specic reference to perpetual type of calendars, whi-ch aim to provide a simple and effective means of indicating the monthly calendai` for any month of years, past, present or future, in both the Julian a's well as the Gregorian system of computation, giving the correct monthly calendar for months of 28," 29, 30 or 31 day length of any year forever starting with the year one A. D.

An important object of my invention is to provide an article of the aforementioned character which is comprised of a static or stationary support section upon which is rotatably mounted a dial; an object of my invention being to provide, by one simple adjustment, in addition to a pre liminary computation in accordance with a table furnished with my invention, thus representing a truly devised computing arrangement which indicates perpetually the calendar dates of months of 28, 29, 30 and 31" day length, for years as well as for leap years.

Another important object of my invention is to provide, in connection with the structure for determining the calendar dates, a numerically arranged table which segregates the years into centuries, decades, and unit years, so that the three may be correlated to give any particular year desired, and thus furnish a table requiring minimum of space, arranged for the greatest convenience and completeness, and showing by a simple formula the centuries repeating in sequence. Starting with the century digits, or the Julian or Gregorian index for the century digits, the sequence is horizontally across a row to the decades digit-s, or tens digits, and thence perpendicularly down a column to the year, or units digit, and subsequently horizontally across a row to the intersection of the fsaid units row with the months column, where will be found the number referring to the calendar number for the month of which there are 28 in number thus furnishing a complete number of combinations and permutations of the seven days of the week with the four lengths of months, such as, namely, months of 28, 29, 30 and 31 day duration.

Another object of my invention is to provide A Another object of my invention is to provide a key opening or index register with which is brought into alignment the numeral representing the Gregorian or Julian index imprinted on a circular dial, the same having first been obtained from the table and computation from the formulas indicated on a portion of the table, and so used in conjunction with the table, to determine the arrangement of days of that particular month for the particular year which it is sought to establish.

An important feature of my invention is to provide a dial which is continuously numbered repeating each of the numbers twice, the number-s being repeated twice beginning with one, and arranged in two intertwined spiral formations so that one spiral is positioned with respect to the other spiral a lead of The distinguishing feature between the two spirals is that the primary spiral begins with one, and the dates are repeated twice and terminates with the number 29 which appears but once, then a space is provided and the numeral 30 appears once, that being distinguished from the secondary interlacing spiral numerical arrangement, which is identically the same, with the exception that it terminates with the numeral 29 being repeated twice, and adjacent thereto, the numeral 30 appears once, then a space between the numeral 30 and the last numeral 31 the said dial is also numerically designated with index numbers beginning with one and continuing in rotation, the one commencing under the second weekly arrangement beginning with the column 4, 11, 18, 25 and being thence consecutively numbered until the ultimate index 28 is reached.

Another feature of my invention is to provide a support of easel-like formation which is co1- lapsible and may be set up flat for transit purposes and mailing, and also which is provided with tab locking means so as to permit rigid triangulation of the support proper resembling an easel stru-cture whereby the article or calendar may be conveniently positioned on a table or desk and conveniently manipulated when it is desired to indicate thereon any particular calendar or date.

Another object of my invention i's to provide an article of the aforementioned character which is practical in construction, useful and efficient for the purposes for which it has been created, and of such simple elemental structure as to warrant economical production thereof in quantity.

Other objects, features, and ancillary advantages reside in certain novel features oi construction, arrangement and combination of parts which will be hereinafter more fully described, and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, in which like symbols are used to designate like parts, and in which;

Fig. lrepresents a front perspective of my invention.

Fig. 2 is a longitudinal cross-sectional vie-w thereof.

Fig. 3 is a rear perspectiveview,pointing lout otherV features of my invention.

Fig. 4 represents the numerical arrangement of the dual spiral formation of calendar yweeks depicted on the dial in order to enable deduction of calendar date's in conjunction with ythe use of the preliminary-vcalculation from the algebraic formulae and tables ,provided therefore. i Fig. 5 vis .ablanklorf'gdevelpment of the easel )structure comprising :one :element of my inven Referring-to the 4various gures, generally, designates my `invention `which is made up of .oneblank (as indicated in Figure 5) consisting' Aof a front portion 1, a rear portion '8, and a lock portion i4 forlocking and securing the three ,portions 1in triangular -or. easel formation. The blank is cut out to the `apprtoiz'nate shape indicated Vin Eigure 5, :and is .provided 'with weakened -lineiportions 4| and!!! to facilitate bending the same so asto 4assemble-'as"indicated Vinigure 1.

.The blankisalso 'cutroutat il'i and it, so that when-fthe samet'isfolded over `to'provide a clear- 'ance.;open`ing .permitting .the edge of the rotatable `dial |2 to :be manipulated 'by the thumb rorifingers, the said-dial being secured by having its'central Vopening 3l secured to theopening @2 by virtue of-a-grommetiz'lwhich 'holds the same .in .assemblage frictionally and movably, maintaining the dial 'iiZzunder islight frictional engagement.withprespect'tofthe 'front portion 'l o1" the structure, generally, designated The blank is `further `recessed in grill-'likeg-formation encompassing -approximately a -senjiicircular area 2F, the grill openings I .9 being ofatrapezoidal shape, though oneiof `the said itrapezoidal .openings des- :ignatedZ'is provided with'a small calendar in- Y 'dex register opening vat its "base designated 2i,

the \purpos'e'f'o'f V.which is` to vbe yhereinafter more yclearly' elucidated..ft-,should'be noted that the -said trapezoidalk openings are evenly spaced by :intermediate areas or portions'.

:The rear portion "8 of the blank `has an enlarged slotted portion l'i merging with a refdued'slottediportion I8 and is also cutout as intimated-ate in order 'to .facilitate rotating the dial l2 zby irictional contact of the fingers with itszedge, in theA eventthat the structure is 'hung .uip'on a wall by means .of the hangingopenings :2 2 -whentheeasel retaining portion 'ifi 'is not "docked in engagement-with the slotted portions 'QH Aand I3. 'When .set-up ineasel formation 'as i 4indicatedinligureL thelocking tab portion i5 "being'spacedffrom the portion ill by virtue of locking slot i6, permits the tab I5 `to enter the fsiot 1H until the reduced neck portion i6 is in 'alignment with the Yside yedges F53 'of the reduced Slot I8 whence the tab Ylli is brought down into locking engagement so that the side walls e3 Ythereof -are'engagng the yslotted portion, or reduced neck 'portion 16, as more clearly indicated ie Figure' 3- Referring to Figure 4, the dial structure which is deemed an important element of my inven tion is indicated in detail, and it comprises, a circular disc designated l2 of suitable diameter having a securing hole at its mid point designated 3l and having imprinted thereon series of numerals in spiral formation arranged consecutively from 1 to 3G on one spiral formation designated 7,2%, and another spiral formation enumerated from 1 to 31, the two spiral enu merations being interwoven and staggered by a differential lead of at the starting point of each spiral formation.

The distinguishing features between these two spirals are that in one case the numerals are duplicated, that is 1 1, 2 2, 3 3, etc., until the numeral 29 is reached which is not repeated, but a blank space is left after the numeral 29 appearing but once, and after the blank space the numeral 30 terminates that Yspiral enumeration; lthe other spiral ,arrangement duplicatesy the numeral"29 but only indicates the numeral f30 once with an intermediate blank spaceand thenterminates with the numeral 3l indicated only once. Thesaid interlaced spiral arrangement provides va series of weeklycalendar dates for the diierent/daysoftheweek and are numbered for Yfurther ,purposes gto vbe hereinafterqmore clearly elucidated, from 1 to 28, respectively, the said enumeration being designated 3o.

On the front portion "lof the-calendar, I indicate the semi-circular area within Ywhich is confinedthe grill section, hereinbefore, referred to and having theslotsfor the openings 'I9 and 2d, also having Iat the top thereof fa legendary indication of 'the days of the week, generally, indicated 25, and the-weekly vdates that happen to coincide or register atthe-i-nstant Ypositioning of the dial l2, -underthe vcalendar index 8.

In this particular calender, 18 vindicates its numerical index characterizedby the-numeral 3o showing the dates of the "week vdesignated in coiumns 3S. All `this material is imprinted on the lower section 23 ofthe iCalendar-portion 1; the upper section-24 thereof :indicating a number of tables and algebraicrformulae -for preliminary computation used `in connection with the determination of certain 'calendar numbers Aor indices. The upper Vsection 24 is sub-divided into a section 32 which contains aseriesfof Calendar numbers falling ineach of yseven Acategories designated by the lettersa, b, c,id,fe, f,g, above which the calendar'months are vindicated as January, February, 'Maron Aprii, May, June, July, August, September, October, November, -and December indicating the respective days therein, and in the months of January and February two columns are indicated fin order to Ytake vcare of the leap years whichhavc a bearingpon the calculation and determination for obtaining Vthe proper calendar `indices i3d. .Above vthe month 'arrangement there is afsection on which, for handy referencaiis provided and Adesignated 3.5. the algebraic formulae gfor Ypreliminary -calculation and determination Aof the rJulian index, or the'Gregorian index; the said formula-e maybe utilized for converting from the Julian yindex to the Gregorian index vvarious calendar dates. Adjacent Vto the section Stand Yto the left thereof, I indicate the columns 36 and 35; the lcolumn 36 indicating Ythe vcentury digits -for Yfour v,Giregorian centuries, namely, 1700, "1800, 1900V and 2000; whereas -theicolumn `S'findicates vtheJulia-n and Gregorian index for all centuries ,as determined by formulae 34. Immediately to the left of the columns 35 and 36 and adjacent or contlguous thereto, I have tabulated the decade table 31, and directly below the same the table 38 the unit or year table. O-n the table in section 32 one column for January is indicated in red, and one column in February is also indicated in red, while on the unit or year table 38 various numerals are indicated in red, the said numerals indicating leap years and when in the determination of a certain calendar index the unit numeral happens to be a red numeral, the numerals aligned in the red column under January and February are to be used as calendar indices.

Since the Gregorian calendar was adopted on September 14, 1752 the arrangement on my table indicates from the seventeenth century on the computation of Gregorian calendars. The use of my calendar for Gregorian yearsl beginning with the seventeenth century is as follows: Example: November 11th, 1918 the first Armistice day. Now to locate the proper calendar index under the Gregorian system of notation, we first locate the century digits 19 above the column of letters a, b, c, etc., and proceed to the left section 31, until the decade digit one is reached, this column is followed down into section 38 to the year digit 8; once that is done the next procedure is to move to the right of the digit 8, thus located, to section 32, and at the intersection of this row and the month column, namely, November the calendar number 28 is found; the dial is then rotated until the number 28 appears in registry or coincidence with the opening 2 I, and the proper calendar is thus set, whence it can be seen that November 11th, 1918 fell on a Monday.

In leap years, the red numbers under January and February are used. If the year digit is red, it indicates a leap year, excepting for those century years in the Gregorian system not divisible by four hundred such as 1700, 1800, 1900, 2100, etc.

In the Julian calendar, which preceded the Gregorian calendar, every year divisible by four is a leap year Without the above exception. The letter to the right of the year digit is the Sunday letter, in leap years it applies only to the last ten months. For all Julian years the computation is as follows: Add the numeral 2 to the century digits and divide by 7; for all Gregorian years take two times the century digits and divide by 8, in either case locate the remainder left after factoring out the divisor and proceed further as follows: Example: October 12th, 1492 Julian calendar 14 plus 2 equals 16; "16 divided by 7 equals 2 and 2 remainder; locate the remainder 2 called the Julian index above the column of letters a, b, c, etc., and proceed to the left until the decade digit 9 is reached in section 31; follow this column down into section 38 to the year digit 2, now move to the right to section 32, and at theintersection of this row and the month October is the calendar number or index 8, turn the dia-l until this number 8 appears in registry with opening 2l and you will have the calendar desired October 12th, 1492 Julian calendar fell on a Friday. This example is depicted and illustrated in the setting of Figure 1.

Another illustration is, for example, using the conversion system from the Julian to the Gregorian calendar; George Washington was born Friday, February 11th, 1732 and according to the Julian formula the remainder is 5, and

the calendar index is 7, whereas according to the Gregorian calendar that date is found in calendar 1 and is February 22nd, 1732.

Another use for my invention is for nding when a certain date will fall on a certain day. Example: When next will July 4th fall on Wednesday? Starting with the smallest calendar number under July which is 2 (see section 32) set the dial at each in turn until the 4th is under Wednesday. The calendar index then showing will be 10. The row containing calendar number 10 under July will also contain the year digit for all years having the 4th of July on Wednesday. Thus we see that 1934 was the last, and 1945 the next year with July 4th on Wednesday. For January and February, this process must be repeated once for each column to find the next regular year and the next leap year that answers the problem.

It should be noted that the algebraic formulae for the Julian and Gregorian calendar indices are equivalent tho not equal since they represent the same period of time in the existence of. the universe, the notation or designation of the said period of time merely diiering according to its designation whether'Julian or Gregorian. The numerals covered with perpendicular section lines designate black letters on a red background or red letters may be imprinted. These red imprints are used for computations involving the leap year.

I believe I have illustrated rather clearly, and described rather succinctly the nature of the construction and use of my invention, but it is readily obvious that changes may be made therein within the spirit and scope of the disclosure, and I reserve the right to any such changes as well as those that fall within the embodiment of the accompanying drawings, also those falling within the purview of the foregoing description.

Having thus described and revealed my invention, what I claim as novel, and desire to secure by Letters Patent, is:

l. A perpetual calendar comprising, a static support having a grilled section, a computing section, and a calendar index register merging with an opening of the said grilled section; and a calendar dial rotatably mounted on the said static support, the said dial having imprinted thereon the numerical days of the month arranged in dual interlaced spiral formations and spaced initially with a starting lead of seven alternate columnar portions Vthereof being exposed simultaneously through the said grilled section, the composite interlacing of the said spiral formations resulting in 28 calendar indices, each of the said indices adapted to be exposed alternately through the said calendar index register, the said numerical days of the month being imprinted twice only up to and including the numeral 28 but all of the numerical days being consecutively arranged for each of said spiral formations, one of said spiral formations terminating with the numeral 30 in which the numeral 29 appears once, the other of said spiral formations terminating with the numeral 31 in which the numeral 29 appears twice and the numeral 30 appears once, the numerals 30 of said one spiral and 31 of said other spiral formation appearing but once in each of said spiral formations and being preceded by a blank space.

2. A perpetual calendar comprising, a static support having a grilled section, a computing section, and a calendar index register merging with an opening of said grilled section; and a @mance Y f? @aleman-,dial rotatably mountedonpthez'said; .static ,support/,fthe :said dial f. having imprinted tnereon the numeral'jdays of the month arranged in -zdllal interlaeed ,spiral lformations and vspaced `initially with a starting:lead `o 180" exposed through the said `gri11ed Sectio,n, the composite interlacing of 1thes ad Aspiral lformations resulting R128 V calendar indices, `each of the said n- -dices y adapted to 'fbe exposed alternatelyv through the -said calendar 'index regis enithe :said oomposite interlacing ofthe said spiral formations registering alternate columnsoffdates with the ,openings in the Vsaid grilled section, the said r1i1,.-merical days of the month Vbeing imprinted qlutqall of; tnenu-merical daysqbeing consecutively arranged -fcr each -o said vspiral formations, one

of :said Spiral formations terminating with .the numeral 30 in whiohrthe numeral 29 appears vormatheiotlrxer of said spi-ralforcrnations termi- ;nating witngthefnumeral 315m Whichjthe numeral 2,9 appears ktwice and -the numeral310 ,appears onoethefnumerals" 30 of :said Aone spiral v.and .31 :of :said .other .spi-ral formation :appearing -but ioncegnfveach1ofsaidspira1 Yformationsandbemg 5 :preceded loy a .,blank space RICHARD 'BLODGET.

REFERENCES l,CITED The ufollowing references are :fof v'record in ,the .file of this patent:

" UNITED STATES PATENTS Number Nllmhel 

